You have a silk pillowcase you like, the care label looks intimidating, and you are wondering whether one wash will turn it into something that no longer fits your pillow. It is a fair worry. Silk is a natural fibre, and natural fibres can change size when they meet water and heat.
The reassuring part is that shrinking is mostly within your control.
The short answer: yes, silk can shrink, mainly from hot water, a tumble dryer or rough handling. Washed cold and gently, and dried in the air, it keeps its size and shape well.
Why silk shrinks
Silk is a protein fibre, a little like hair. When the fibres get wet they absorb water and relax. When they dry, they tighten again. If heat or strong agitation is added at any point, the fibres and the weave can draw closer together than before, and the fabric ends up slightly smaller.
So water alone is not really the problem. The combination of water, heat and movement is.
What makes shrinking more likely
| Cause | What happens | What to do instead |
|---|---|---|
| Hot or warm water | Fibres tighten and the color can dull | Wash in cold water |
| Tumble dryer | Heat and tumbling shrink and roughen the fabric | Air dry in the shade |
| Long soaking | Fibres stay swollen for longer than they need to | Keep the wash short |
| Fast spin or wringing | The weave is pulled and twisted | Gentle cycle, press water out with a towel |
| Harsh detergent or bleach | The fibre is weakened and loses its smoothness | pH-neutral or silk detergent |
Does it shrink on the first wash?
Any natural fabric can settle a little the first time it is washed, and silk is no exception. With a cold, gentle wash this is usually slight, and you are unlikely to notice it on a pillowcase.
What people remember as "my silk shrank" is nearly always a warm wash or a spin in the dryer. If you want to understand the dryer question in detail, we have a separate guide: can you put silk in the dryer.
How to wash silk so it keeps its size
- Read the care label. It always comes first.
- Use cold water. By hand, or on a gentle or delicates cycle.
- Choose a pH-neutral or silk detergent. No bleach and no fabric softener.
- Use a mesh laundry bag in the machine. Turn the piece inside out and close the zipper first.
- Keep it short. Silk does not need a long soak.
- Do not wring. Lay the piece on a clean towel, roll it up and press gently.
- Dry in the shade. Flat or over a wide rail, away from direct sun and radiators.
- Smooth it into shape while it is damp. This matters more than people expect.
For the full routine, including stains and storage, see how to wash and care for your silk pillowcase.
What to do if your silk already shrank
Be honest with yourself about what is possible. Shrinking from heat is hard to reverse, and you should not expect a piece to return fully to its original size. Still, a gentle attempt costs little.
- Soak the piece briefly in cold water with a small amount of silk detergent.
- Press out the water in a towel. Do not twist.
- Lay it flat and ease it back toward its shape with your hands, a little at a time. Do not pull hard.
- Let it dry flat in the shade.
- Finish with steam or a low iron on the reverse side while it is slightly damp.
Often the fabric relaxes a little, and it also feels softer again. If it does not, a slightly snug pillowcase is still usable on a flatter pillow.
Does the size or closure matter?
A pillowcase should have a little room around the pillow. That ease means a slight change after washing does not affect the fit. If your pillow is very full, or sits between two sizes, the larger case is the more forgiving choice.
KINT pillowcases come in Standard at 20 x 26 inches, Queen at 20 x 30 inches and King at 20 x 36 inches, in 19 or 22 momme. You can compare them in our silk pillowcases. An envelope closure gives a touch more tolerance than a zipper, because the flap simply overlaps a little less.
Questions people ask
Does silk shrink in cold water?
Very little, if at all, when the wash is gentle and the piece dries in the air. Cold water is the safe choice for exactly this reason.
Does heavier silk shrink less?
Heavier silk is denser and tends to hold its shape well, but any silk can shrink with heat. The way you wash it matters more than the weight.
Will an iron shrink silk?
Not on a low or silk setting. A hot iron can damage the surface, so keep the heat low and iron the reverse side while the fabric is slightly damp.
Treated gently, silk keeps its size for a long time. If you are choosing a first pillowcase, the Mulberry Silk Pillowcase 22 Momme is a good place to start, and our guide to how long silk pillowcases last explains what to expect over the years.
